Abstract The Pliensbachian-Toarcian sedimentary rocks of the Median Subbetic (Betic Cordillera, SE Spain) were deposited in the South Iberian Palaeomargin under hemipelagic conditions. In the Arroyo Mingarron section (SE Spain) these deposits are composed by a marl and marl and limestone alternation with abundant radiolarians. The application of magnetic susceptibility and gamma ray spectrometry to these deposits allows to interpret environmental changes related to the fluctuations in the continental influx of terrigenous and phytodetritus to a hemipelagic setting in the South Iberian Palaeomargin. The increase of terrigenous input was coincident with the negative carbon isotopic excursion (CIE) at the base of the NJT6 nannofossil Zone that correlates with the Jenkyns Event. The increase of Th and K content is related to enhanced detrital input, especially oxides and silicates, including clay minerals. The gamma ray signal derived from U is comparatively low with respect to K and Th. Nevertheless, the U content shows an increase in the base of NJT6 nannofossil Zone that indicates a relative increase of organic matter content coincident with the Jenkyns Event. Changes in the calcareous nannofossil assemblages at the beginning of the NJT6a nannofossil Subzone and, in particular, the sharp decrease in abundance of the species Mitrolitus jansae during the negative CIE of the Jenkyns Event are interpreted as related to sea-water stratification and a probable poor oxygenation making inhospitable the deep photic zone during this event.

中文翻译：

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整合伽马射线光谱法、磁化率和钙质纳米化石以解释环境扰动：来自伊比利亚南部古边缘（西班牙东南部亚贝蒂中部）的詹金斯事件（下托阿尔阶）的一个例子

摘要 中亚贝蒂（Betic Cordillera，SE西班牙）的Pliensbachian-Toarcian沉积岩在半远洋条件下沉积在南伊比利亚古边缘。在 Arroyo Mingarron 部分（西班牙东南部），这些矿床由泥灰岩、泥灰岩和石灰岩交替组成，并具有丰富的放射虫。将磁化率和伽马射线光谱法应用于这些矿床，可以解释与陆源和植物碎屑大陆流入南伊比利亚古边缘半远洋环境的波动有关的环境变化。陆源输入的增加与与 Jenkyns 事件相关的 NJT6 纳米化石区底部的负碳同位素偏移 (CIE) 一致。Th和K含量的增加与碎屑输入增强有关，尤其是氧化物和硅酸盐，包括粘土矿物。从 U 导出的伽马射线信号相对于 K 和 Th 来说相对较低。然而，U 含量显示 NJT6 纳米化石带底部的增加，表明有机质含量的相对增加与 Jenkyns 事件同时发生。NJT6a 纳米化石亚区开始时钙质纳米化石组合的变化，特别是在 Jenkyns 事件的负 CIE 期间，Mitrolitus jansae 物种丰度的急剧下降被解释为与海水分层和可能的贫在此事件期间，氧合作用使深光区变得不适宜居住。U 含量显示 NJT6 纳米化石区底部的增加，表明有机质含量与 Jenkyns 事件同时发生相对增加。NJT6a 纳米化石亚区开始时钙质纳米化石组合的变化，特别是在 Jenkyns 事件的负 CIE 期间，Mitrolitus jansae 物种丰度的急剧下降被解释为与海水分层和可能的贫在此事件期间，氧合作用使深光区变得不适宜居住。U 含量显示 NJT6 纳米化石区底部的增加，表明有机质含量与 Jenkyns 事件同时发生相对增加。NJT6a 纳米化石亚带开始时钙质纳米化石组合的变化，特别是在 Jenkyns 事件的负 CIE 期间，Mitrolitus jansae 物种丰度的急剧下降被解释为与海水分层和可能的贫在此事件期间，氧合作用使深光区变得不适宜居住。